CHAPTER XIV.
WIRELESS TELEGRAPHY.
In Chapter XII. we showed how Dr. Hertz caused electric waves to pass through space and become visible by sparks across an air gap in a wire ring situated at a distance from the source of energy. The apparatus used, and termed an electric resonator, is in principle similar to that of the wireless telegraph. The minute sparks instead of idly passing across the air gap are made to traverse a "coherer" (to be afterwards more fully described). This "coherer" substantially consists of a resistance, preferably metal filings placed in series, with a battery and relay. Normally, the resistance is so adjusted that the battery current is not strong enough to operate the relay. A wire is led from one side of this coherer up into the air to intercept the Hertzian waves, the other side of the coherer is put to earth, or "grounded." When a wave strikes the air wire it sends a current through the coherer to ground (as before it sent a spark across the air gap), and this wave acts on the filings in its passage through them; in effect, to lower their resistance, so that the current is increased through the relay circuit and the relay armature is attracted to its magnet. The relay makes contact in the usual manner at the platinum points, and in its turn causes the local circuit, sounder, bell, or pen register to record the wave (or signal). After each wave the filings are in such state that to restore them to their former high resistance it is necessary to give the coherer a smart tap. This is generally accomplished automatically by means of an arm extending from the sounder lever, which strikes against the coherer each time the sounder armature is moved.
Figures 74 and 75 are diagrams of a simple circuit, Fig. 74 being the transmitting apparatus and Fig. 75 the receiving apparatus.
In Fig. 74 _P P_ and _S S_ are the primary and secondary of a Ruhmkorff coil, _D_ two brass balls on the discharger, _B_ the battery, _K_ a key, in place of the usual contact breaker, which is either absent or screwed down; _V_ a wire leading from one arm of the discharger up into the air, of a height varying with the results desired; _G_ a ground plate in connection with the other discharger arm.
The coil condenser is left out of the diagram for sake of clearness; but, of course, is necessary to the operation of the apparatus.
In Fig. 75, _C_ is the coherer, also called the Branly tube, or radio conductor; _S_ a telegraph sounder, or electric bell; _R_ a relay; _R B_ and _L B_ the relay battery and local battery, respectively; _G_ a ground connection; _M_ a resistance, or choke coil, and _V_ a vertical wire, as in the transmitter; in fact, in the station set the same vertical wire answers for both transmitter and receiver.
The coil to be used may be from two inches of spark upwards, dependent upon the distance the signals have to travel. The relay battery may be two cells of dry battery, the local battery as much as is desired to operate the bell, sounder, or pen register receiving the signals. Presuming the apparatus set up and adjusted, and designating the transmitter as Station A and the receiver as Station B, the operation will be as follows: A pressure and release of key _K_ sends an impulse of current through the primary _P_, inducing a current in _S_, which manifests itself by a spark between the discharger balls at _D_. An electric wave is released, which, starting from _V_, Station A, meets in its passage _V_ of Station B. Travelling along this wire to the ground, it finds two paths—through _C_ or _R_. As the choke coil deters it from passing through the relay, it finds passage through _C_ and so to ground.
THE COHERER.
Many forms of this apparatus are in use, but as yet no definite design can be recommended for specific purposes. The most general mode of construction is that of the Branley Coherer, as shown in Fig. 76.
It consists of a glass tube, 2 inches long by ¼ inch inside diameter, furnished with well-fitted metal plugs at each end, to which connections are made. These plugs can be slid in and out of tube for adjustment, the gap between them being loosely filled with fine metal filings. The metal used varies, according to the operator's preference, the most generally adopted being pure nickel for both plugs and filings. Another mode of construction for purely experimental use is to merely cork the ends of the tube and pass the wires through these corks into the filings, ensuring, however, good contact between wires and filings. Marconi's favorite form is a glass tube two inches long with silver plugs, each one-quarter inch long, in each end, intervening space being partially filled with a mixture of nickel and silver filings. These plugs are then adjusted to as close as one-twenty-fifth of an inch, and the whole apparatus exhausted of air either by means of a leading-in tube or by placing coherer in a vessel from which the air can be drawn. As a rule, coherers containing air become less sensitive after continued use.
CARBON COHERER.
Pointed carbon rods can be inserted in the tube instead of metal, and carbon dust substituted for the metal filings; but this form is suitable only for special purposes. It is very delicate in its action, but somewhat uncertain.
COHERER WITHOUT FILINGS.
Were it not for reasons, such as difficulty of decoherence, the metal filings might be dispensed with and two rods of metal placed in light contact. The construction of the coherer reminds one very much of the microphone, a satisfactory coherer having been made out of the old "nail microphone," four wire nails being placed crossing one another in the battery circuit, in one case acting as a sound transmitter, whence the name; in the other as a coherer.
ALUMINIUM COHERER.
Aluminium, a metal which has steadily grown into favor, and which is now readily obtainable, can be made to serve in the present apparatus in place of nickel both as to electrodes and filings. It is advisable, however, to use aluminium electrodes of slightly larger diameter than those of other metals.
STEEL BALL COHERER.
A recent writer has recommended the use of balls of steel, such as are used in ball bearings, such, however, not to exceed ⅜ inch diameter. Such a coherer would take the form of an upright glass tube, with electrodes exerting pressure on a series of four or more steel balls. Decoherence here becomes difficult, and mention is but made of it to show the variety of forms which this important little article may assume.
Coherers are adjusted by advancing or receding the electrodes, altering the quantity of the filings, etc. There exists but little difficulty in operating coherers; considerable latitude is permissible as to adjustment, size, character, etc. There does not seem so much difficulty in obtaining sensitiveness as in guarding against external electrical disturbances. Wings or vanes of thin sheet metal are sometimes attached to the metal ends or electrodes of the coherer for purposes of adjustment, their size and capacity being determined by experiment. It is best that they present no sharp angles, but be of a disc, or spherical, form, the better not to dissipate energy.
THE OSCILLATOR.
This is the name given the contrivance at the ends of the discharger, _D_ being the point at which the electrical oscillations, or waves, are radiated.
CLARKE'S OSCILLATOR.
This consists of two brass spheres, generally 3 inches in diameter, and mounted on a stand or sometimes on top of the induction coil. The distance between the balls is readily adjustable by either attaching the balls on the ends of two sliding rods, or causing the balls themselves to slide on the rods (Fig. 77).
TRIPLE OSCILLATOR.
Here three balls are used, two outside ones connected to the circuit, being one-half inch diameter, and the middle one, isolated from all connection, of three inches in diameter. This form is best mounted on a separate stand, the balls either being on glass or hard rubber legs (Fig. 78). Connecting wires from the secondary of the coil must in all cases be run with the greatest precautions against crosses, as directed in Chapter V.
It is possible to make many different designs in oscillators. Some experimenters use the simple Clarke form, others prefer the triple balls; yet, again, others vary the sizes and the relative sizes of the balls. One form of oscillator prescribes the balls to be immersed in oil or vaseline. Such methods all have their adherents. Even the plain points of an induction coil discharger will serve for short-distance work.
Oscillators are adjusted by altering their proximity to one another, and should have care given to keep the spheres bright. It is easy to alter capacity of an oscillator by connecting its spheres to other insulated spheres.
THE COIL.
The coil for wireless telegraphy does not differ from the regular Ruhmkorff, except that in place of the contact breaker a signal or Morse telegraph key is substituted. Of course, the contact breaker can be made to perform the same duty by retracting the adjusting screw out of reach of the platinum on spring, and then operating the hammer and spring in same manner as key.
TRANSLATING DEVICES.
Under this head are included relay sounder, bell, or register, which are at receiving set. They do not differ from the regular telegraphic apparatus. The sounder may be of the Western Union pattern, wound to 4 ohms; the relay also Western Union pattern, and wound to 150 or 250 ohms, as best suits the individual case.
In order to protect the receiver from the action of the transmitter belonging to the same set of instruments, particularly when powerful waves are generated, it has been found at times necessary to enclose the receiver in a metal case. Marconi has patents on such devices, particularly on a movable shutter in the case, which opens when the transmitter is not in operation. Edouard Branly placed his receiving set in a metal case with a vertical slit eight inches by one-tenth of an inch.
AIR CONDUCTOR.
The vertical wire extending from the coherer up into the air must be insulated from all other objects in the best possible manner. A bare copper wire of No. 14 B & S gauge can be suspended from porcelain insulating knobs, which in turn can be strung from each other by means of stout silk cord or even wire. There is a special form of insulator used in electric construction work, and known as a circuit breaker, which will answer and which is easy of attachment; reference to Fig. 79 will show manner of using.
Temporary grounds can be made to water pipes, but it is better to use regular telephone copper ground-plates sunk deep in moist earth.
At South Foreland, England, a mast has been erected, 150 feet in height for transmission across Channel, a distance of nearly thirty miles. At Notre Dame University, Illinois, Professor Green used a wire 150 feet in length, suspended from top of a high church tower, but was unable to transmit much over three miles, owing, presumably, to fact that the intervening country was well supplied with overhead wires, which probably intercepted the waves.
It has been claimed that earthed or grounded air wires are necessary, but balls or similar "capacities" are not of service on the top of the wire. A theory has been advanced that the currents do not pass from air wire tip to air wire tip, but are conducted by the varying strata of the earth. No general confirmation is obtainable, however, and the experimental reader will find a wide field for research in this direction. Marconi, on the other hand, has accomplished much with zinc cylinders under six feet high, _not grounded in any respect_, indeed, and he also finds it impossible to assume a proportion between distance of effect and height of air wire. The following investigations and experiments are of interest in this connection:
At a meeting of the Institution of Electrical Engineers, in December, 1898, Dr. Oliver Lodge showed that there must be a certain relative position between the receiving and transmitting circuits.
He placed on one side of a room a box, containing a battery, bell, relay, and coherer properly connected up. On the other side he had an induction coil and pair of parallel discharger rods, with a spark gap to transmit waves across the room. When the rods of the receiver and transmitter were placed parallel to each other the receiving bell was operated; when the receiving rods of the transmitter were at right angles to those of the receiver the bell either failed to work, or weakened very considerably. He also told of an experiment made to determine the influence of different methods of grounding the apparatus. He found that when the apparatus was connected by a wire laid on the ground, there was the required response at the receiving station; but when the two stations were situated each side of a lake, and the ground wires immersed in the water, the receiving instrument failed to work. It seemed to him that the conductivity and power absorption of ether wave energy by water was too great to allow of the transmission of Hertz waves. This would seem to bear out the results obtained by Marconi in dispensing with ground wires.
INDEX.
A
Acid, Chromic, 189.
" Sulphuric, 212.
Air pump, Geissler, 142.
" " Simple, 141.
" " Sprengel, 143.
" blast, 76.
" wire, 262.
Amalgamation, 180.
Assembly of coil, 22.
Attraction, Window, 154, 163.
Automobile coil, 40.
Automatic burners, 170.
Automatic burners, Adjustment, 176.
B
Ballistic galvanometer, 99.
Barium platino cyanide, 238.
Base for coil, 30.
Bath coil, 61.
Battery, Bichromate, 180.
" Champion, 179.
" Daniell, 191.
" Dun, 187.
" Edison-Lalande, 195.
" Fuller, 184.
" Gas-lighting, 179.
" Gethins, 193.
" Gordon, 194.
" Gravity, 191.
" Grenet, 180.
" Harrison, 219.
" Monarch, 179.
" Morisot, 188.
" Novelty, 182.
" Open circuit, 178.
" Polarization, 179.
" Samson, 179.
" solutions, 185, 188, 189.
" Standard dry, 196.
" Storage, 200.
" Storage, to charge, 208.
" Storage, to make, 101.
" Storage, to seal, 215.
" U. S. storage, 218.
Beeswax, 95.
Brush, Electric, 128.
C
Capacity of condenser, 100.
Carbons for battery, 182.
Cements, 97.
Charging condenser, 110.
Chromic acid, 189.
Closed magnetic circuit, 6.
Coherer, Aluminium, 251.
" Branly, 254.
" Carbon, 256.
" Steel ball, 258.
Coil, Failure to work, 49.
" for gas engine, 37.
" general remarks, 42.
" in series, 32.
" Medical, 51.
" Oil immersed, 33.
" Output of, 46.
" Primary, 7.
" Resistance, 40.
" Secondary, 10.
" Table of dimensions, 50.
" Tesla, 35.
" Testing, 44.
" To select, 46.
" Winding, 20.
Condensers, Aluminium, 115.
" Adjustable, 117.
" Charging, 110.
" capacity, 100, 119.
" Discharge of, 225.
" Glass, 101.
" Mica, 108.
" Oil, 116.
" Paper, 105, 107.
" Rolled up, 115.
" Series, 108.
Cone vibrator, 88.
Contact breaker, 26.
" " Adjustable medical, 85.
" " Adjustable cone, 88.
" " Dessauer, 80.
" " Electrolytic, 77.
" " Highspeed, 69.
" " in vacuo, 81.
" " Polechanging, 73.
" " Queen, 83.
" " Queen, large form, 84.
" " Steel ribbon, 80.
Contacts, Care of, 90.
Core, 4.
" Iron filing, 46.
Crookes tube, 241.
D
Dessauer contact breaker, 80.
Dielectric, 104.
Discharger, 26.
Dry cell, 196.
Dun cell, 187.
E
Eddy currents, 6.
Edison-Lalande cell, 195.
Electric sand, 189.
Electrode, 190.
Electrolyte, 213.
Electrolytic interrupter, 77.
Ends for coil, 25.
Extra current, 3.
F
Farad, 100.
Fluoroscope, 239.
Fluorescence, 137.
Foucault currents, 6.
Frauenhofer lines, 135.
Frontispiece, Notes on, 42, 47.
G
Galvanometer, 99.
Gas burners, 170.
" engine coil, 39.
" from water, 44.
" lighting, 164.
Gassiot star, 153.
Geissler tube, 159.
Glass, To pierce, 130.
Gordon battery, 194.
H
Harrison cell, 219.
Hertz resonator, 226.
Hydrometer, 211.
Hysteresis, 6.
I
Induction, 1.
" Self, 8.
Insulations, 97.
L
Leyden jars, 99.
Lighting gas, 164.
M
Magnetic circuit, Closed, 6.
Medical coils, 51.
" " Care of, 62.
Mercury contact breaker, 71.
Mica condenser, 61.
N
Noise of contact breaker, 63.
O
Oil, Capacity of, 119.
" Coil immersion, 33.
" for oscillator, 260.
" Linseed, 93.
" Resin, 96.
" Spark through, 95.
Oscillator, 258.
" Clarkes, 259.
" Triple, 259.
Output of coil, 46.
P
Paper condenser, 107.
Paraffin, 94.
Phosphorus tube, 239.
Photography, X-Ray, 245.
Pocket coil, 89.
Polarity tests, 45.
Pole, 190.
Polechanging switch, 32.
Polechanging contact breaker, 73.
Primary coil, 7.
Q
Queen contact breaker, 83.
" Crookes tube, 241.
R
Radiography, 245.
Reel ends, 25.
Resistance coils, 40.
Resonance, Electric, 226.
Resonator, Hertz, 226.
Rheotome, 2.
Roentgen Ray apparatus, 236.
Rotating wheel, 154.
S
Series, Coils in, 32.
Selection of coil, 46.
Shellac, 96.
Signs, Battery, 190.
Soda, Bichromate of, 183.
Spark, Electric, 120.
" Choice of, 47.
Spectroscope, 132.
Spectrum, Solar, 132.
Standard dry cell, 196.
Sulphating, 215.
Switch, Polechanging, 32.
T
Table of cost, 191.
Tesla coil, 35.
" " disruptive, 36.
Testing polarity, 46.
Transformer, 5.
Tube, Insulating, 9.
U
U. S. storage cell, 218.
V
Vacuum, Adjusting, 242.
" Choice of, 243.
" Contact breaker, 81.
" To procure, 141.
" pumps, 140.
W
Water, Decomposition of, 44.
Wax, 95.
Wehnelt interrupter, 77.
Wheel, Rotating, 154.
Winder, Coil, 16.
Winding coils, 20.
" Secondary, 10, 14.
" Sectional, 11.
Wire for secondary coil, 24.
" " primary coil, 9.
Wires, Air, 262.
Wireless telegraphy, 248.
Wireless telegraphy circuit, 250.
X
X-Ray apparatus, 236.
" Remarks, 243.
" photographs, 246.
BIBLIOGRAPHY
_GENERAL REFERENCE_
=Electricity, Its Theory, Sources and Applications=, by JOHN T. SPRAGUE. 3rd edition.
=Induction Coils and Coil Making=, by F. C. ALLSOP.
=The Construction of Large Induction Coils=, a Workshop Handbook, by A. THARE. Illustrated.
=A Manual of Electricity=, by H. M. NOAD, Ph.D. London, 1859. (_Scarce._)
=Practical Electrics.=
=Sloane's Electrical Dictionary.=
=Houston's Electrical Dictionary.=
=Electricity and Magnetism=, by PROF. SILVANUS P. THOMPSON.
_BATTERIES_
=Small Accumulators and How to Make Them=, by P. MARSHALL.
=Primary Batteries=, by H. S. CARHART.
=Practical Electrics.=
=Electric Batteries, How to Make Them=, by P. MARSHALL.
_WIRELESS TELEGRAPHY_
=A History of Wireless Telegraphy=, by J. J. FAHIE.
=Improvements in Magnetic Space Telegraphy, Telegraphing by Magnetic Induction, and Aetheric Telegraphy=, by SIR W. H. PREECE, S. EVERSHED, and OLIVER LODGE.
=Science Abstracts, Physics and Electrical Engineering.=
=The Model Engineer and Amateur Electrician.=
Queen Instruments
_Induction Coils_ capable of producing thick, heavy sparks from 60" to ¼" in length. Made in 15 different styles for either direct or alternating currents of any voltage.
_X Ray Tubes_ which have an automatic vacuum regulating device by means of which rays of penetrating power can be obtained. Our tubes have large, clear bulbs with a great current capacity and sharp definition.
_Fluoroscopes_ of Platino Barium Cyanide or Calcium Tungstate with removable screens. Permanent and brilliant.
_Accessories_—such as Tube Stands, Independent Vibrators, Wehnelt Interrupters, Localization Apparatus, Protecting Screens, Radiographic Table, X Ray Plates, Storage Batteries, Motor Transformers, Archives of the Roentgen Ray—everything to make X Ray Work simple and successful.
Electrical Testing Instruments, Meters, Photometric Apparatus
Queen & Co. (Incorporated)
J. G. GRAY, President
59 Fifth Avenue New York
1010 Chestnut Street Philadelphia, Pa.
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Technical Cyclopedia in 5 Vols.
First Series.
Principal Contents.—Bronzes, Cements, Dyeing, Electro-metallurgy, Enamels, Etchings, Fireworks, Fluxes, Fulminates, Gilding, Gums, Japanning, Lacquers, Marble Working, Nitro-Glycerine, Photography, Pottery, Varnishes. 420 pages, 103 illus., cloth, $2.00.
Second Series.
Principal Contents.—Acidimetry, Albumen, Alcohol, Alkaloids, Bitters, Bleaching, Boiler Incrustations, Cleansing, Confectionery, Copying, Disinfectants, Essences, Extracts, Fire-proofing, Glycerine, Gut, Iodine, Ivory Substitutes, Leather, Matches, Pigments, Paint, Paper, Parchment. 485 pages, 16 illus., cloth, $2.00.
Third Series.
Principal Contents.—Alloys, Aluminium, Antimony, Copper, Electrics, Enamels, Glass, Gold, Iron, Steel, Liquors, Lead, Lubricants, Magnesium, Manganese, Mercury, Mica, Nickel, Platinum, Silver, Slag, Tin, Uranium, Zinc. 480 pages, 183 illus., cloth, $2.00.
Fourth Series.
Principal Contents.—Water-proofing, Packing, Stowing, Embalming, Preserving, Leather Polishes, Cooling Air and Water, Pumps and Siphons, Dessicating, Distilling, Emulsifying, Evaporating, Filtering, Percolating, Macerating, Electrotyping, Stereotyping, Book-binding, Straw-plaiting, Musical Instruments, Clock and Watch Mending, Photography. 443 pages, 243 illus., cloth, $2.00.
Fifth Series.
Principal Contents.—Diamond Cutting, Laboratory Apparatus, Filtering, Magic Lanterns, Metal Work, Percolation, Illuminating Agents, Tobacco Pipes, Taps, Tying and Splicing Tackle, Repairing Books, Netting, Walking Sticks, Boat-Building. 440 pages, 373 illus., cloth, $2.00.
EACH SERIES has its own Contents and Index and is complete in itself.
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Cleaning and Scouring
A MANUAL FOR
DYERS AND LAUNDRESSES
And for Domestic Use.
_BY S. CHRISTOPHER._
CONTENTS.
DRESSES.—Silk, Satin, Irish Poplin and Tabinet, Llama, Alpaca, Printed Muslin and Pique, Pique and Colored Muslin.
SHAWLS AND SCARVES.—China Crape, Brocaded or Printed Silk, and Woolen.
SILK HANDKERCHIEFS, RIBBONS, MANTLES, FANCY WAISTCOATS, AND LACE. GLOVES.—Kid, Washleather.
FEATHERS.—White, Colored; to purify—for Beds, &c.
BONNETS.—Chip, Straw, and Leghorn. ANCIENT TAPESTRY.
CURTAINS, BED FURNITURE, &C.—Chintz, Damask, Worsted-and-cotton Damask, French Damask—Silk-and-worsted Moreen, Tabaret or Tabbarea, Satin, Tammy Lining, Fringes—Bullion and worsted, Lace and Gimp—Bullion.
TABLE COVERS.—Silk-and-worsted, Cotton-and-worsted, and Printed Cloth.
CARPETS.—Dry Cleaning, thorough Cleaning.
HEARTHRUGS, SHEEPSKIN RUGS AND MATS.
TO REMOVE VARIOUS STAINS FROM LINEN AND COTTON.—Fruit Stains, Grease Spots, Ink Stains, Marking Ink, Mildew, Paint or Varnish, Wine Stains.
RECIPES FOR GENERAL DOMESTIC USE.—Oilcloth, Paint, Floors, Marble, Iron and Steel, Brass or Copper, Silver Plate, Furniture, Gilt Frames, Ivory Ornaments, Mirrors, Wall-paper, Stone Steps.
DEFINITIONS, &C.—Boards, &c., for French Cleaning, Camphine, Common Sour, Drying, Frame, French Board, Hot Stove, Irons, Parchment Size, Pegs, Puncher, Size, Soap, Starch, To Handle, To Sheet-up, Water.
Price 20 cents, post-paid.
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THEORETICAL AND PRACTICAL
Ammonia Refrigeration
_A Work of Reference for Engineers and others Employed in the Management of Ice and Refrigeration Machinery._
By ILTYD I. REDWOOD
CONTENTS
B. T. U. Mechanical Equivalent of a Unit of Heat. Specific Heat. Latent Heat. Theory of Refrigeration. Freezing, by Compressed Air. Ammonia. Characteristics of Ammonia. The Compressor. Stuffing-Boxes. Lubrication. Suction and Discharge Valves. Separator. Condenser-Worm, Receiver. Refrigerator or Brine Tank. Size of Pipe and Area of Cooling Surface. Charging the Plant with Ammonia. Jacket-Water, for Compressor, for Separator. Quantity of Condensing Water Necessary. Loss due to Heating of Condensed Ammonia. Cause of Variation in Excess Pressure. Use of Condensing Pressure in Determining Loss of Ammonia by Leakage. Cooling Directly by Ammonia. Freezing Point of Brine. Making Brine. Specific Heat of Brine. Regulation of Brine Temperature. Indirect Effect of Condensing Water on Brine Temperature. Directions for Determining Refrigerating Efficiency. Equivalent of a Ton of Ice. Compressor Measurement of Ammonia Circulated. Loss of Well-Jacketed Compressors. Loss in Double-Acting Compressors. Distribution of Mercury Wells. Examination of Working Parts. Indicator Diagrams. Ammonia Figures—Effectual Displacement. Volume of Gas. Ammonia Circulated per Twenty-Four Hours. Refrigerating Efficiency. Brine Figures-Gallons Circulated. Pounds Circulated. Degrees Cooled. Total Degrees Extracted. Loss due to Heating of Ammonia Gas. Loss due to Heating of Liquid Ammonia. Calculation of the Maximum Capacity of a Machine. Preparation of Anhydrous Ammonia. Construction of Apparatus, etc., etc.
150 pages, 15 illustrations, cloth, $1.00.
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LUBRICANTS,
OILS AND GREASES
Treated Theoretically and Giving Practical Information Regarding Their
COMPOSITION, USES AND MANUFACTURE
BY ILTYD I. REDWOOD
CONTENTS
INTRODUCTION.—Lubricants.
THEORETICAL.—Chapter I. Mineral Oils: American and Russian; Hydrocarbons. Chapter II. Fatty Oils: Glycerides; Vegetable Oils; Fish Oils. Chapter III. Mineral Lubricants: Graphite; Plumbago. Chapter IV. Greases: Compounded; "Set" or Axle; "Boiled" or Cup. Chapter V. Tests of Oils: Mineral Oils. Fatty Oils.
MANUFACTURE.—Chapter VI. Mineral Oil Lubricants: Compounded Oils; Debloomed Oils. Chapter VII. Greases: Compounded Greases; "Set" or Axle Greases; Boiled Greases; Engine Greases. Appendix. The Action of Oils on Various Metals. Index.
TABLES.—I. Viscosity and Specific Gravity. II. Atomic Weights. III. Origin, Tests, Etc., of Oils. IV. Action of Oils on Metals.
LIST OF PLATES.—I.—I. I. Redwood's Improved Set Measuring Apparatus. II. Section Grease Kettle. III. Diagram of the Action of Oils on Different Kinds of Metals.
8vo, cloth, $1.50.
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PRACTICAL HANDBOOK ON
Gas Engines
With Instructions for Care and Working of the Same.
_BY G. LIECKFELD, C.E._
Translated with permission of the Author by _GEORGE RICHMOND, M.E._
WITH A CHAPTER ON OIL ENGINES
CONTENTS
Choosing and installing a gas engine. The construction of good gas engines. Examination as to workmanship, running, economy. Reliability and durability of gas engines. Proper erection of a gas engine. Foundation. Arrangement for gas pipes. Rubber bag. Locking devices. Exhaust pipes. Air pipes. Setting up gas engines. Brakes and their use in ascertaining the power of gas engines. Arrangement of a brake test. Distribution of heat in a gas engine. Attendance on gas engines. General remarks. Gas engine oil. Cylinder lubricators. Rules as to starting and stopping a gas engine. The cleaning of a gas engine. General observations and specific examination for defects. The engine refuses to work. Non-starting of the engine. Too much pressure on the gas. Water in the exhaust pot. Difficulty in starting the engine. Irregular running. Loss of power. Weak gas mixtures. Late ignition. Cracks in air inlet. Back firing. Knocking and pounding inside of engine. Dangers and precautionary measure in handling gas engines. Precautions when opening gas valves, removing piston from cylinder, examining with light openings of gas engines. Dangers in starting, cleaning, putting on belts. Oil Engines. Gas engines with producer gas. Gasoline and oil engines. Concluding remarks.
120 pages, illustrated, 12mo, cloth, $1.00.
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The Best and Cheapest in the Market
ALGEBRA SELF-TAUGHT
FOR THE USE OF
Mechanics, Young Engineers and Home Students
_BY W. PAGET HIGGS, M.A., D.Sc._
FOURTH EDITION
CONTENTS
Symbols and the signs of operation. The equation and the unknown quantity. Positive and negative quantities. Multiplication, involution, exponents, negative exponents, roots, and the use of exponents as logarithms. Logarithms. Tables of logarithms and proportional parts. Transportation of systems of logarithms. Common uses of common logarithms. Compound multiplication and the binomial theorem. Division, fractions and ratio. Rules for division. Rules for fractions. Continued proportion, the series and the summation of the series. Examples. Geometrical means. Limit of series. Equations. Appendix. Index. 104 pages, 12mo, cloth, 60c.
_See also_ Algebraic Signs, Spons' Dictionary of Engineering, No. 2. 40 cts.
_See also_ Calculus, Supplement to Spons' Dictionary, No. 5. 75 cts.
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THE
FIREMAN'S GUIDE
A Handbook on the Care of Boilers
_BY KARL P. DAHLSTROM, M.E._
CONTENTS OF CHAPTERS
I. Firing and Economy of Fuel.—Precautions before and after starting the fire, care of the fire, proper firing, draft, smoke, progress of firing, fuel on the grate, cleaning out, cleaning grate bars and ash pan, dampers, firing into two or more furnaces, dry fuel, loss of heat.
II. Feed and Water Line.—Feeding, the water line, false water line, defective feeding apparatus, formation of scale, gauge cocks, glass gauge, the float, safety plug, alarm whistle.
III. Low Water and Foaming or Priming.—Precautions when water is low, foaming, priming.
IV. Steam Pressure.—Steam gauge, safety valves.
V. Cleaning and Blowing Out.—Cleaning the boiler, to examine the state of the boiler, blowing out, refilling the boiler.
VI. General Directions.—How to prevent accidents, repairs, the care of the boiler when not in use, testing boilers, trimming and cleaning outside. Summary of rules. Index.
8vo, cloth, 50 cents.
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THE CORLISS ENGINE.
BY JOHN T. HENTHORN.
AND
MANAGEMENT OF THE CORLISS ENGINE.
BY CHARLES D. THURBER.
_Uniform in One Volume. Cloth Cover; Price, $1.00._
Table of Contents.